Will this video pass the upload?
Drop a video. Its file is read the way an upload is checked — codec, frame rate, size, length, index — against TikTok's, Instagram's and YouTube's published rules.
Runs in your browser. Nothing is uploaded, no signup.
Watch an example
13 seconds · a made-up example
Videos made in the studio come out as vertical H.264 + AAC MP4 files.Join the beta
How it works
Short and checkable: every limit links to the platform's own page, read on 28 Oct 2026.
The file is read, not played
An MP4 or MOV is a stack of labelled boxes. The checker reads their headers and the index box (moov) straight from your disk: the codec, the exact frame rate from each frame's timing, the real video bitrate from the size of every frame, the sound, and where the index sits. A 4 GB file takes a few reads.
Each platform's rules for its official upload
TikTok's Content Posting API and Instagram's API publish their limits; YouTube says which uploads count as Shorts. Each line shows the rule, your value and its source. A value the checker could not read says so — it never passes by default.
A fix you can run yourself
When something fails, you get the ffmpeg command that fixes it: move the index to the front, re-encode to H.264 at 30 fps, trim to the limit. ffmpeg is free and runs on your own computer.
What it doesn't do
- It doesn't read WebM or MKV boxes: for those, only length and picture size come from your browser.
- It doesn't check two things Instagram's spec also asks for: closed GOP and 4:2:0 colour sampling.
- It doesn't know your account's own limits: TikTok may allow less than 10 minutes on yours, and YouTube needs a verified account over 15 minutes.
- Your file never leaves this device. Nothing is uploaded or kept.
Questions
Why does my video fail to upload on TikTok or Instagram?
Usually the codec (Instagram wants H.264 or HEVC; TikTok also takes VP8 and VP9), the frame rate, the size (Instagram: 300 MB for a Reel through the API) or an index placed at the end of the file. Drop the file to see which rule it misses and the ffmpeg line that fixes it.
What is the moov atom, or faststart?
The index of an MP4 file. When it sits at the end, a player or an upload has to read the whole file before it can start. ffmpeg's -movflags +faststart moves it to the front.
Is my video uploaded?
No. The file is read in your browser, in small pieces; nothing is sent to us or anyone else.
Sources
- 1TikTok for Developers — Content Posting API — media transfer guideupdated 4 Aug 2026 · read 28 Oct 2026
- 2Meta for Developers — Instagram API — IG User Media, Reel specifications and captionAPI v26.0 · read 28 Oct 2026
- 3YouTube Help — Square or vertical videos up to 3 minutes are Shortsuploads since 15 Oct 2024 · read 28 Oct 2026
- 4YouTube Help — Upload limits: 256 GB or 12 hoursover 15 min needs a verified account · read 28 Oct 2026
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Made to spec, posted for you.
Vertiscale renders every video as H.264 with AAC sound and publishes it to each of your accounts through the official APIs. Publishing is in beta: TikTok posts stay private until our app passes TikTok's review.